1. Field of the Invention
The present invention broadly relates to thrust reversing in gas turbine engines and, more particularly, is concerned with an improved reversing system in which blocker devices located in the divergent section of the exhaust nozzle are linked with deflector devices located in its convergent section.
2. Description of the Prior Art
Gas turbine engines incorporated in military and commercial aircraft often include variable area exhaust nozzles as well as thrust reversing systems. Typically, a variable exhaust nozzle is movable between a closed position wherein it defines a minimum exhaust are a for cruise and other low power modes and an open position wherein it defines a maximum exhaust area for takeoff and other high power modes. A thrust reversing system ordinarily is deployed during approach and landing when the exhaust nozzle is in its closed, minimum area position.
One recent thrust reversing system is disclosed and illustrated in U.S. Pat. No. 4,382,551. It is particularly advantageous when used with gas turbine engines requiring variable area convergent/divergent exhaust nozzles. It employs reverser doors which are part of and carried by the nozzle flaps of the already existing variable area exhaust nozzle. Elimination of the need for separate structures to carry the reverser doors results in a significant weight savings and drag reduction.
Although the thrust reversing system of the aforementioned patent has satisfactorily met its intended objectives, it and other axisymmetric reversing systems occasionally incur sudden throat shifts due to uneven engine flowrates during transition between forward and reverse thrust conditions. Consequently, a need exists for improvement of reversing systems which avoid problems associated with uneven engine flowrates without creating added weight and drag problems.